The Great China Corporation Telephone State 4296 Importers Cable Address "Chinaco" Chicago Exporters Chemists Engineers HEAD OFFICE—6th Floor, Lees Bldg., 19 S. Wells St., Chicago, U. S. A. Branches and Agencies in China and all over the World 1 IMPORT AND EXPORT DEPARTMENTS Our Chemical and Engineering Staff will quote on any chemicals or machinery or equipment. They will give estimates and data on complete plants for all kinds of industries. Prompt shipment guaranteed. Our experience in Chinese trade is large and varied, and inquiries are welcomed. Kindly mention THE CHINESE STUDENTS' MONTHLY when writing to advertisers. Entered as second-class matter, December 4, 1920, at the Post Office at Hittorf or Crookes Tube How Were X-Rays Discovered? IR James Mackenzie Davidson visited Professor Roentgen to find out how he discovered the X-rays. Roentgen had covered a vacuum tube, called a Hittorf or Crookes tube, with black paper so as to cut off all its light. About four yards away was a piece of cardboard coated with a fluorescent compound. He turned on the current in the tube. The cardboard glowed brightly. Sir James asked him: "What did you think?" "I didn't think, I investigated," said Roentgen. He wanted to know what made the cardboard glow. Only planned experiments could give the answer We all know the practical result. Thousands of lives are saved by surgeons who use the X-rays. Later on, one of the scientists in the Research Laboratory of the General Electric Company became interested in a certain phenomenon sometimes observed in incandescent lamps. Others had observed it, but he, like Roentgen, investigated. The result was the discovery of new laws governing electrical conduction in high vacuum. Another scientist in the same laboratory saw that on the basis of those new laws he could build a new tube for producing X-rays more effectively. This was the Coolidge X-ray tube which marked the greatest advance in the X-ray art since the original discovery by Roentgen. Thus, scientific investigation of a strange phenomenon led to the discovery of a new art, and scientific investigation of another strange phenomenon led to the greatest improvement in that art. It is for such reasons that the Research Laboratories of the General Electric Company are continually investigating, continually exploring the unknown. It is new knowledge that is sought. But practical results follow in an endless stream, and in many unexpected ways. General Electric Schenectady, 95-460-FBI |